1. Field of the Invention
The present invention relates generally to a portable information terminal and, more particularly, to a portable information terminal unit of a type in which a display and a pressure-sensitive input device overlying the display are assembled in its unit body and in which a cover for covering the pressure-sensitive input device is attached to the unit body in a freely openable and closable manner.
2. Description of the Related Arts
Hitherto known as equipment in the field of portable information terminals are products such as "ZAURUS PI-4000" (SHARP Co.) or "NEWTON" (Apple Computer, Inc.) having function of personal information management. In each of these products its unit body includes a liquid crystal display and a transparent pressure-sensitive input device laid over the surface of the liquid crystal display. The pressure-sensitive input device allows the operator to enter characters by tracing its surface with an input pen and to enter a specific function by operationally pressing a function pad appearing on the surface thereof.
The unit body is provided with an opening and closing cover attached thereto for covering the pressure-sensitive input device, so that the pressure-sensitive input device would be protected during out-of-operation. However, there has never existed such products that make it possible to execute the data entry with the input pen or the function pad while the cover is closed. Accordingly, irrespective of how frequent a specific function is used, the cover always must be opened whenever the pressure-sensitive input device is intended to be operated or pressed. Furthermore, when using the input pen in place of the pressing operation with a finger, the frequent pen entry would subject the pressure-sensitive surface of the pressure-sensitive input device to accelerated deterioration.
A remote controller of a video tape recorder is one of the information equipment with a cover attached. For instance, the remote controller of a video tape recorder VZ-H330 supplied by SANYO ELECTRIC CO. comprises, as shown in FIG. 7, a unit body 103 including a plurality of key pads 101 and a display screen 102. A selective operation of the key pads 101 allows the operator to enter a variety of functions into the main videotape recorder remote from the controller. For instance, the pressing of an UP channel key pad 104 enables the television channel to sequentially shift up, whereas the pressing of a DOWN key pad 105 enables the channel to sequentially shift down.
The unit body 103 is provided with an opening and closing cover 106 attached thereto for covering the key pads 101 and the display screen 102. As shown in FIG. 8, the cover 106 is provided with an UP channel button 107 and a DOWN channel button 108, which are both exposed on the surface of the cover 106 in a state where the cover 106 is closed. Upon pressing the UP channel button 107 with the cover 106 closed, the base end of the button 107 mechanically depresses the UP channel key pad 104 of the unit body 103, allowing the channel to shift up. And also, the pressing of the DOWN channel button 108, with the cover 106 closed, allows the channel to shift down. In this manner, only frequently operated buttons are exposed on the surface of the closed cover 106, which prevents the key pads covered by the cover 106 from being erroneously or unexpectedly operated. Of course, when the cover 106 is opened, any further various functions can be achieved.
However, in such information equipment with a cover, the operating buttons on the cover are mechanically connected to the corresponding key pads of the unit body, which requires the strict alignment between the bases of the operating buttons and the corresponding key pads. This means that the positions of the cover side operating buttons depend to some extent on the positions of the unit body side key pads. Accordingly, the variation of the design can be restricted and the operability of the information equipment cannot be improved any more. In addition, some measures are needed for causing a pressing force from the cover side operating button to uniformly act on the unit body side key pads so as to ensure reliable actions of the key pads. Furthermore, even in the case of exchange of the covers, since the unit body side key pads only achieve predetermined functions, the versatility would be low.